Urban forests affect land surface temperature (LST) within a city due to the cooling effect of transpiration. The latter depends on tree health, but it can also be affected by the structure and composition of forest, as a mono-species environment may potentially worsen the health of urban forest. The following hypotheses are therefore proposed: a) greater tree diversity within urban forest results in lower LST at the city block scale; and b) the state of biotic disturbance of urban forest is negatively correlated with LST. The present research explores the relationship between urban forest tree diversity and health based on a survey of 38,950 individuals in the district of Providencia in the city of Santiago, Chile, and compares this information against LST data from the ASTER satellite instrument at the city block scale. The health of the urban forest was determined by expert knowledge means of a field survey that collected data concerning growth stage, phytosanitary state, and state of biotic disturbance. The first hypothesis could not be tested by the lack of urban tree diversity which showed strong domination of three species with more than 52% of abundance (Robinia pseudoacacia, Platanus orientalis and Acer negundo). The second hypothesis was proved since the results revealed a positive and significant correlation between urban forest diversity and LST, with a Spearman’s correlation coefficient of between 0.56 and 0.7. A positive and significant correlation of 0.55 was found between mean biotic disturbance (BDSm) and median LST (Med), indicating a direct relationship between higher LST and poorer urban forest health. A possible explanation is that, among the trees surveyed within the urban forest, the effect of biotic disturbance is greater than that of species diversity. As such, it may be concluded that planting of trees on city streets as a means of temperature moderation is made less effective if specimens are maintained in a poor general condition of health.

由于蒸腾作用的降温作用，城市森林影响着城市内部的地表温度（LST）。后者取决于树木的健康状况，但也可能受到森林结构和组成的影响，因为单一物种的环境可能会恶化城市森林的健康状况。因此提出以下假设：a）城市森林中树木的多样性增加，导致城市规模的LST降低；b）城市森林生物干扰状况与LST呈负相关。本研究基于对智利圣地亚哥市普罗维登西亚地区38,950个人的调查，探索了城市林木多样性与健康之间的关系，并将该信息与ASTER卫星仪器在街区范围内的LST数据进行了比较。 。城市森林的健康状况是通过现场调查的专业知识手段确定的，该调查收集了有关生长期，植物检疫状况和生物干扰状况的数据。第一个假设无法通过缺乏城市树木多样性来证明，该树木多样性显示了超过52％的丰富度的三种树种的强势统治（刺槐，侧柏和黑枫）。第二个假设得到了证明，因为结果表明城市森林多样性与LST之间存在正相关和显着相关，Spearman相关系数在0.56至0.7之间。平均生物扰动（BDSm）与中位LST（Med）之间存在0.55的正相关和显着相关，表明LST较高与城市森林健康状况较差之间存在直接关系。一个可能的解释是，在城市森林中被调查的树木中，生物干扰的影响大于物种多样性的影响。因此，可以得出结论，如果将标本保持在较差的总体健康条件下，在城市街道上植树作为降低温度的手段将变得无效。